[clang-format] Add a NamespaceEndCommentsFixer

Summary:
This patch adds a NamespaceEndCommentsFixer TokenAnalyzer for clang-format,
which fixes end namespace comments.
It currently supports inserting and updating existing wrong comments.

Example source:
```
namespace A {
int i;
}

namespace B {
int j;
} // namespace A
```

after formatting:
```
namespace A {
int i;
} // namespace A

namespace B {
int j;
} // namespace B
```

Reviewers: klimek, djasper

Reviewed By: djasper

Subscribers: klimek, mgorny

Differential Revision: https://reviews.llvm.org/D30269

llvm-svn: 296341

1 files changed, 10 insertions, 2 deletions

diff --git a/clang/lib/Format/UnwrappedLineParser.h b/clang/lib/Format/UnwrappedLineParser.h
index 6cea8cdc036..15d1d9cda7a 100644
--- a/clang/lib/Format/UnwrappedLineParser.h
+++ b/clang/lib/Format/UnwrappedLineParser.h
@@ -48,6 +48,14 @@ struct UnwrappedLine {
   bool InPPDirective;
 
   bool MustBeDeclaration;
+
+  /// \brief If this \c UnwrappedLine closes a block in a sequence of lines,
+  /// \c MatchingOpeningBlockLineIndex stores the index of the corresponding
+  /// opening line. Otherwise, \c MatchingOpeningBlockLineIndex must be
+  /// \c kInvalidIndex.
+  size_t MatchingOpeningBlockLineIndex;
+
+  static const size_t kInvalidIndex = -1;
 };
 
 class UnwrappedLineConsumer {
@@ -234,8 +242,8 @@ struct UnwrappedLineNode {
   SmallVector<UnwrappedLine, 0> Children;
 };
 
-inline UnwrappedLine::UnwrappedLine()
-    : Level(0), InPPDirective(false), MustBeDeclaration(false) {}
+inline UnwrappedLine::UnwrappedLine() : Level(0), InPPDirective(false),
+  MustBeDeclaration(false), MatchingOpeningBlockLineIndex(kInvalidIndex) {}
 
 } // end namespace format
 } // end namespace clang